Re-land [dsymutil] Upstream update feature

This commit attempts to re-land the r324480 which was reverted in
r324493 because it broke the Windows bots. For now I disabled the two
update tests on Windows until I'm able to debug this.

Differential revision: https://reviews.llvm.org/D42880

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@324592 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed